In 45 years of entertaining, whether in the bawdiest of New York’s bath houses, the most intimate cabarets and lounges, the toniest big-city concert halls or the most cavernous arena across the globe, Bette Midler has pretty much done it all. Like her contemporaries, be they Cher, Neil Diamond, Rod Stewart, Barry Manilow, heck even the Rolling Stones — they of a certain age group — Midler crafted and cultivated a unique sound in the music business.

On more than two dozen albums, the three-time Grammy winner delivered her sound. Unmistakably hers. In her live shows, Midler was chameleon-like, transforming from a Broadway diva to Las Vegas showgirl to a swear-like-a-sailor rocker to a smoldering torch singer to a wailing mistress of soul. And there were always showers of sequins to add just the right amount of mischievous razzle-dazzle.

And though her resume boasts everything from Broadway plays and television shows to feature films (she was Oscar-nominated for her roles in the 1979 film “The Rose” and 1991’s “For the Boys”) and a Las Vegas residency, Midler says it’s music that has always propelled her.

Which brings us to Midler’s first U.S. trek in 10 years, her 22-city Divine Intervention tour, which kicked off last month in Florida. Backed by a 14-piece orchestra and her backup trio of Harlettes, the singer is touring behind her latest CD “It’s the Girls!,” an homage to the harmony-rich girl groups of the ’30s,’ 40s, ’50s and ’60s, with a stripped-bare, piano lounge cover of TLC’s “Waterfalls” thrown in for good measure.

Gone, Midler says, is much of the shtick that defined her live performances for decades. “It’s time to say goodbye to [Midler’s mermaid alter ego] Dolores [Delgado],” Midler says matter-of-factly. “But I have a few surprises in store.”

Though Midler is now 69, the new album finds her completely in her comfort zone, on classic multilayered harmony hits such as “Tell Him,” “Be My Baby,” “Mr. Sandman” and the album’s title track (a sparkling homage to the 1930 Boswell Sisters’ hit “It’s the Girl”).

During a recent phone conversation amid final rehearsals for the tour, Midler talked about returning to the road.

Bette Midler | COURTESY OF WARNER BROS. RECORDS

Q.Your new album pays homage to some of the great girl groups of pop and doo-wop. Why did you decide to cover this genre?

A. From the beginning of my career I’ve been singing songs like “Leader of the Pack,” “Da Do Ron Ron.” The first song I heard in my own home was “It’s The Girl.” I have tremendous affection for all these songs. I played them constantly since I was very young, maybe 5 or 6. I’ve just always loved girls groups and that harmony they produced. I had thought about singing those songs for many years and then just put it aside. But after all I’ve been through, and I’ve been through every oeuvre there is, I decided to just do it.

Q.What was it like to work with composer/arranger Marc Shaiman again, specifically for the gorgeous arrangements for the CD?

A. It was great. I’ve worked with him since I was 16. He has a really good ear for that kind of thing. He credits me with showing him that there was more music in the world than just what he was listening to. And he has a real affection for the material, too. I really do trust his ear and his arrangements. I always have.

Q.The harmonies on the new album are a marvelous revelation, but you’ve always had a knack for delivering multi-layered vocals that are seamless and right on target.

A. I work very hard on harmonies. I love singing harmony parts. Been doing them since the first record I made. When I was first singing in clubs with a small band with [Barry] Manilow [on piano] they’d sing background and I’d sing lead. .. Harmonies are very intricate but I found I could learn them. … I never belonged to a glee club. Never sang a cappella. I had a trio, though. I sang with two other girls in Hawaii [where Midler was born and raised). We used to sing folk songs on the military bases. We had a beautiful sound. I always wanted to sing harmonies.

Q.How did you decide which songs to take on for the project?

A. We went through a whole bunch of songs to see if I could sing them seriously. I definitely knew I wanted “Waterfalls,” “(Talk to Me of) Mendocino,” “One Fine Day” and “It’s the Girl.” And “Bei Mir Bist Du Schon” [by the Andrew Sisters]. My folks used to sing that one around the house all the time.

Q.Did you try to find songs that you could personally relate to?

A. It’s always very helpful for you to bring a backstory to a song. It makes it more fun to sing. You can live in that space again.

Q.Do you still find touring to be exciting?

A. It’s totally crazy. I’ll tell you what I really love about being on the road: The food. I can’t wait for the food. It’s gonna be wall-to-wall barbecue! I’m so glad it’s summer. All that corn to look forward to! I can’t wait to go to all the fabulous Chicago restaurants!

Q.What do you do to stay in shape, especially with the demands of life on the road?

A. I’m doing it all. I still run but it tires me out. But I do it because it’s really good for your breathing. I do all the warm-ups and warm-downs for my voice.

Q.Are you happy with your voice nowadays?

A. I think it sounds okay. It’s a muscle. If you keep it and look after it, it will look after you. I think there’s a certain dangerous age past which people really do fail vocally especially if they did crazy things in the 20s and 30s, things like smoking and drugs. .. I’m just trying to live every day [to the fullest], give my love to those I care about, live every day like it was my last.

Bette Midler performs in concert at the Boondall Entertainment Centre on April 8, 2005 in Brisbane, Australia. The singer is currently in the midst of her first tour in 10 years. | Photo by Jonathan Wood/Getty Images

Q. Sounds like a bucket list kind of commentary. What’s the top item on your list?

A. I would like to see South America. I’ve never toured there. I’m madly in love with the glorious artwork and culture. I guess the list would also include just traveling the world, eating fabulous food and meeting people. And just laughing my ass off. That’s it! That’s No. 1 on my bucket list!

Q.How do you still find the joy in music?

A. The thing about music is that it’s as big as the cosmos, but it’s also internal. It’s 4 trillion miles high. There’s no way to encompass all of it. Every day you hear it differently and every day it means something different to you. It’s never become stale to me. It’s always a challenge and thrilling. Music never stands still for me. Every time you sing a song it’s completely different from the last time you sang it. That’s a big reason I still do it.